The National Institute of Mental Health (NIMH) has made a substantial commitment to research designed to discover autism’s causes and improve diagnosis and treatment. Not only has NIMH become the lead institute for autism research at NIH, we have become the largest single source of funding for autism research in the country.

Why has NIMH taken on this leading role in autism research? While included in the Diagnostic and Statistical Manual of Mental Disorders*, autism is usually considered a developmental disorder rather than a mental illness. Why would NIMH commit essential resources to a non-mental illness? Though there are several factors responsible for this, the main driving force behind NIMH’s focus on autism is the evolving view of mental disorders as developmental brain disorders. In that sense, rather than being an exception, autism has become a prototype for understanding a range of mental disorders, from schizophrenia to anxiety disorders.

The notion of mental disorders as developmental brain disorders is a profound shift for NIMH. How can late life depression or PTSD or the behavioral aspects of neurodegenerative disorders be addressed as developmental brain disorders? The answer lies in understanding the trajectory of each of these illnesses, recognizing that behavioral signs and symptoms are often late manifestations of disease. The report that teenagers with APOE4 alleles have an increased risk for Alzheimer’s disease reminds us that brain changes may precede cognitive or behavioral changes by decades. (Shaw, Lancet Neurology 2007) While we do not yet have the evidence for such early changes in schizophrenia or mood disorders or PTSD, an emerging perspective includes all of these disorders as disorders of brain circuits. As the circuits are elaborated early in development through the actions of genes and environment (including experience), it seems entirely plausible that these disorders will someday be detected years prior to the manifest symptoms by alterations in the flow of information through specific neural circuits. We know from the rest of medicine that early detection and early intervention yield some of the greatest improvements in public health.

This makes autism especially relevant. Autism is the paradigmatic developmental brain disorder, with genomic and environmental factors leading to onset in the first three years of life. In contrast to schizophrenia, with onset in late adolescence, or mood disorders, which may not emerge until adulthood, autism provides a foreshortened window of risk that potentially allows a more rapid solution to the problem of genes, environment, and their interaction. Current studies following the younger siblings of children with autism, beginning in the second trimester, can yield critical information that should be informative for a basic understanding of brain development; this includes the variable process for circuit development and predictors of subsequent risk or resilience. Most important, early detection confers the opportunity for early intervention and even preemption of the disability associated with this disorder.

These are exciting times in autism research, with multiple risk genes identified and the beginning of an effort to identify environmental factors. Curiously, many of the genetic lesions associated with autism appear to be associated with schizophrenia and other mental disorders (Rapoport, JAACAP 2009). So progress in autism research may be a fast track to progress in the ambitious mission of NIMH, to prevent and cure mental illness.

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* The DSM is a manual published by the American Psychiatric Association and used by mental health professionals, describing mental health disorders for children and adults, including known causes, age of onset, prognosis, and information on treatment approaches.